Power cylinders and pistons for hydraulic presses, jacks and the like



Nov. 5, 1957 NTZ 2,811,950

G. B. E POWER CYLINDERS AND PISTONS FOR HYDRAULIC PRESSES, JACKS AND THELIKE Filed NOV. 6, 1953 2 Sheets-Sheet 1 FIG. f' 2 I 9 IN VENTOR GerhardB. Emz

M, WWW

ATTORNEYS Nov. 5, 1957 e. B. ENTZ 2,811,950

POWER CYLINDERS AND PISTONS FOR HYDRAULIC PR JACKS AND THE LIKE FiledNOV. 6, 1953 ESSES 2 Sheets-Sheet 2 FIG. 6

INVENTOR Gerhard B. Emz

gwz fi zzv ATTORNEYf United States Patent POWER CYLINDERS AND PISTONSFOR HYDRAU- LIC PRESSES, JACKS AND THE LIKE Gerhard B. Entz, OklahomaCity, Okla., assignor to Southwest Industrial Products, Inc., OklahomaCity, Okla., a corporation of Oklahoma Application November 6, 1953,Serial No. 390,526

Claims. (Cl. 12138) This invention relates to units of hydraulic systemsand more particularly to improvements in the upright power cylinders andvertically movable pistons of such mechanisms as hydraulic presses,jacks and the like.

The invention has been found particularly useful as a part of thehydraulic systems of machines for cutting stone, of the generalcharacter shown in Patent 247,569 to Maxim, dated September 27, 1881. Insuch machines upper and lower sets of chisels are provided, betweenwhich the stone to be cut is disposed, and while the upper set ofchisels may be mechanically or hydraulically held against movement afterthey have been brought into tight engagement with the upper surface ofthe stone, the lower set of chisels in particular are initially elevatedinto tight contact with the lower surface of the stone, at which timethere is no splitting or dividing pressure exerted upon them, andsubsequently pressure applied at about twelve hundred pounds, which,through the chisels, will separate one piece of stone from the other. Insuch machines a plurality of side-by-side power cylinders and associatedpistons are generally provided, because of the width of the machine, andthe relatively wide stone slabs to be cut into pieces.

I have discovered that if the power pistons do not apply substantiallyuniform pressure to the stone to be cut, particularly during thisseparating phase of the cycle of operation in cutting stone,andthroughout the length of the zone where it is desired that the cutoccur, unwanted breakage will result, the stone wanted in strip-likeform cut from the slab Will be in several short pieces. Also if there isnot this substantially uniform pressure, the machine will be subjectedto undesirable shock, evidenced by -a sudden jerk before or when thebreak occurs in the stone, and the chisels at one zone will be relievedof compression before the compressive force upon the chisels is relievedat another zone or zones.

I have also discovered that this jerky operation and undesirable stonebreakages is due in part to air entrained in the hydraulic liquid, suchas oil, accumulating beneath the bottom of the piston, in the lowerportion of the cylinder. There the air must first be compressed to someextent before the full presure of the hydraulic liquid is transmitted tothe piston.

One of the principal objects of this invention is to provide verticallymovable pistons so constructed and arranged that this accumulation ofair in the power cylinder may be bled therefrom as soon as the operatornotices the system is sluggish, that is, slow in operating or there isthis undesirable jerk during operation.

Another object is to provide upright cylinders and companion pistons foruse in hydraulic systems, of the character described, constructed andarranged to collect and conserve motive liquid, such as oil, which findsits way past the bottom of the piston to the space between thecylindrical portions of the companion cylinder and piston. Thiscollection and conservation of the motive liquid also promotescleanliness and reduces the likelihood of the stone being stained by theliquid or the machine and the Patented Nov. 5, 1957 clothing of theworkmen becoming unsightly as often occurs where there is leakage of theliquid.

A further object is to provide as a part of a power piston of thischaracter, a flexible cup-disk packing and a spreader for the flangethereof, the spreader being fabricated in such manner as to effectivelyforce the flange into intimate contact with the bore of the companioncylinder, without likelihood of injuring the packing disk.

Other objects and advantages will appear in the following detaileddescription of two embodiments of the present invention, taken inconnection with the accompanying drawings, forming a part of thisspecification, and in which drawings:

Fig. l is a view partly in central vertical section and partly inelevation of one form of combination cylinder and piston for use in ahydraulic system, a typical load member being shown by dot and dashlines.

Fig. 2 is a bottom plan View on a reduced scale of a ported follower fora flexible cup-disk packing forming a part of the piston.

Fig. 3 is a bottom plan view of the piston shown in Fig. 1, on a reducedscale.

Fig. 4 is an enlarged detail view of a ported bolt used to retain theflexible cup-like packing and associated parts to the lower piston headand to provide a way for passage of fluid through said head.

Fig. 5 is a bottom plan view, on a reduced scale, of the flexiblecup-disk packing.

Fig. 6 is a plan view, on a reduced scale, of a washer used with aspreader in association with said packing.

Fig. 7 is a View similar to Fig. 1, but showing a modified form ofcombination cylinder and piston.

In the drawings I disclose an upright cylinder 3 open at its upper endfor the reception of a drum-like piston 9, preferably made of steel, asshown in Fig. 1, or a drumlike piston 10, preferably made of cast iron,as shown in Fig. 7.

The cylinder 8 is preferably made to comprise a cylindrical body portion11, such as of seamless, soft steel tubing and a head 12 at its lowerportion, also of steel, welded to the bottom of this body portion, suchas by welds 13 and 14. An entrance and exit way 15 for fluid to and froma chamber 16 at the lower portion of the cylinder, above the head 12 isprovided, in the example shown, by securing, as by weld 17, a nipple 18communicating with a hole 19 in the body portion 11, and a pipe 20screwed into nipple, the pipe being connected to suitable fluid pressuresource (not shown).

For a purpose to be subsequently set forth, the cylindrical body portion11 is provided with a circumferentially extending groove 22 open to itsinterior adjacent the upper end 23 thereof, the lower wall 24 of thegroove being beveled, as at 25, downwardly and inwardly. Also, an exitway 26 leads from groove 22 through the wall of the cylinder and has apipe 27 communicating with way 26 to carry liquid which finds its way tothe groove 22 to any suitable receptacle (not shown).

The piston 9 shown in Fig. 1 is preferably made of three parts, acylindrical body portion 28 of seamless steel tubing, heat treated torender it very hard, so as to Withstand the high pressures and vibrationas when breaking stone; an upper head 29 of steel, secured to the upperend of body portion 28 as by weld 3t); and, a lower head 31 of steel inthe form of a disc, secured to the bottom of body portion 28 as by weld32. The head 29 in the example shown is a disc of greater diameter thanthe external diameter of body portion 23 so that it may come to restupon the upper end 23 of cylinder 8 and limit downward movement of thepiston with respect to the cylinder. The upper head 29 may have a loadmember 33 resting upon it, such as a movable beam of a The head 29 is 3provided with a transverse opening 34, preferably ofi-set with respectto the axis of the piston and located near the interior of thecylindrical wall of the piston, so as to permit the load member 33 to becentered above the piston and spread a considerable distance toward theopening 34. The lower head 31 is provided with an axial opening 35,preferably screw threaded, so as to receive the screw threaded shank 36of a ported bolt 37, shown in Fig. 4. This bolt, in the example shown,serves as a part of means 38 for escape of air in chamber 16, entrainedby the usual motive liquid, such as oil, to the atmosphere through theupper piston head 29, and also to retain a flexible cup-disk packing 39,a follower 40, a spreader 41 and a washer 42 in place, as shown in Figs.1 and 3.

I have found, over an extended period of time, that steel is the mostsatisfactory material for use in making the pistons, since it does nottend to twist or break under strain and the steel parts are more readilywelded together than cast iron and steel or even cast iron parts.However, since steel is not at times available for general manufacturingpurposes or on the restricted list, such as during war or otheremergencies, I have conducted tests using cast iron pistons 10, such asis shown in Fig. 7, where the cylindrical body portion of the piston 45and a lower head 46 is an integral casting of iron, while an upper 47may be of cast iron or steel, secured in place as by socket capscrews48. As in the other form of piston, the upper head 47 is provided withthe offset opening 34 and the lower head 46 is provided with the screwthreaded opening 35. I have found, however, that the cast iron pistonstend to yield under pressure which causes welding to break.

The flexible cup-disk packing 39 is well known in the art and comprises,as in Figure for example, a flat body portion 56 and a downturnedannular flange 51 for intimate contact with the bore of the cylinder 8.The body portion 50 has a centrally located hole 52 through which theshank of bolt 37 extends as shown in Figs. 1 and 7.

As to follower 49, shown particularly in Figure 2, it functions like anordinary follower associated with a cup-disk packing but in additionthereto serves, in the example shown, as a part of the means 38 ashereinafter described. With this in view, the follower of disk-likeshape, has a centrally located hole 53 for the shank of bolt 37, andradially extending grooves 54 open to its lower suface and to the hole53 as well as the periphery of the body of the follower.

With reference to the spreader 41, it preferably is made of springsteel, and is of improved formation. It comprises a disk-like body 55(Fig. 3) provided with a centrally located hole 56, for the shank ofbolt 37, and fingers 57 extending radially from and disposed indownwardly and outwardly angular relation to the body 55, the outer endportions 58 of the fingers each being curled to substantially asemi-circle with the convex faces-of the curls of the fingers engagingthe inner face of flange 51 near its free edge. By this construction thelife, so to speak, of the cup-disk packing is prolonged, and likelihoodof the motive liquid finding its way to the space between thecylindrical portions of the companion cylinder and piston is reduced toa minimum.

The washer 42, shown particularly in Figure 6, is of ordinary formationand may be made of cold rolled steel. It has a central opening 59through which the shank of bolt 37 extends when the parts are assembledin the relationship shown in Figs. 1, 3 and 7.

The bevel 25 of groove 22 facilitates assembly of the pistons 9 and intheir respective cylinders, since the spreader 41 functions to springthe flange 51 of packing 39 outwardly. When the piston is started in theopen end of the cylinder, access may be had to the flange 51 to force itinwardly in order to clear the cylinder end, but when the flange 51reaches the groove 22, it is sprung outwardly to a slight extent andwere it not for the bevel 25 further descent of the piston in thecylinder would be impeded.

The bolt 37, in order to function as a part of means 38, in the exampleshown has an axial port 60 in the shank 36 open at the end thereofopposite the bolt head 63, and a diametrical port 62 open to the innerend of port 60. When the bolt is in place in screw threaded engagementwith the threaded opening 35 of the piston and the packing 39, follower40, spreader 41 and washer 42 in proper relationship to one another, thebolt is turned tight with the port 62 in communication with the grooves54.

The means 38 for escape of air in chamber 16, comprises in the exampleshown, the bolt 37 and follower 40, previously described, and, as shownin Fig. 1, bleeder pipe 64, the lower end of which is secured to theupper surface of head 31, as by weld 65, and in communication with theopening 35, while the upper end portion of the pipe extends through andbeyond the opening 34 in head 29, being welded thereto as by weld 66.The upper end of the pipe 64 may normally be closed by means of areleasable plug 67, such as a plug in screw threaded engagement with theinterior of the upper end portion of the pipe. I have found that whenthe piston is made to comprise the body portion 28, and the heads 29 and31 of steel, welded together, the pipe 64 may be of solid or rigidmaterial, in contradistinction to flexible pipe, without likelihood ofthe welds 65 and 66 breaking when the hydraulic system is subjected tohigh pressure and the stresses and strains, as well as vibration, whenthe system forms a part of stone cutting machinery.

When the piston is made mainly of cast iron, such as is shown in Fig. 7,I have found the piston would yield under pressure to which it issubjected in stone cutting machinery, and the welding of a solid orrigid pipe, such as is shown in Fig. 1, would break. The means 38 forescape of air in chamber 16 of this type of cylinder and pistoncombination, where the latter is mainly of cast iron, comprises, in theexample shown, the follower 40 and a bolt 37, the shank of which issufficiently long to extend through and upwardly beyond the opening 35,also an externally threaded nipple 70 which extends through the opening34 in head 47 and may be in screw threaded engagement with the head orwelded thereto, as by welds 71, and a flexible bleeder pipe 72 providedwith an upper coupling 73 and a lower coupling 74. The coupling 73 hasdetachable connection with the lower end portion of nipple 70 and thecoupling 74 has detachable connection with the upper end portion of bolt37. I may also, for convenience, include as a part of means 38, an elbow75, one leg of which is in screw threaded engagement with the upper endof nipple 70 and the other leg pointed away from the axis of the piston,the latter leg receiving a reducer 76. The outer end of the port ofreducer 76 is normally closed by means of a plug 77.

It will be noted that the pipes 64 and 72 are disposed in the spacedefined by the heads and the body portion of their respective drum-likepistons, where they are in protected positions and no expensivemachining or molding of parts is necessary in order to provide thisbleeder means in relatively large units.

Should motive fluid in chamber 16 find its way past the packing 39, itis forced upwardly betwen the cylinder and piston until it enters thegroove 22 from which it may be removed, such as by gravity flow, forreuse or disposal as desired and such escaping fluid is not scatteredabout the machine or workmen in proximity to it.

The bleeding means 38 is normally sealed against escape of fluidtherefrom by means of the plugs 67 or 77, as the case may be. When anoperator notices that the pressure of the piston, when applied, is slowin its build-up, and then is applied with a sudden jerk, he is apprisedthat air has entered the system and is below the piston in the chamber16 of the cylinder. This slowness is caused by the compression of theair which,

when compressed to its maximum, causes the piston to move upward with ajerk. The workman then opens the bleeding means, such as by the removalof the plug 67, or 77, as the case may be, while the piston is in araised position and pressure is being applied. The air then rushes outof the various ports and ways provided for its escape and when liquid,such as oil, begins to issue from the outlet normally plugged, thebleeding means is closed 01f, such as by the replacing of the plug. Whenbleeding means 38 is first opened to the atmosphere, under suchconditions as above set forth, liquid will not rush out, because anyliquid which has filled the bleeding means as a result of a priorbleeding operation will have found its way back into the chamber 16,because it is heavier than air, and will be displaced by air entrainedwith the motive liquid.

I claim:

1. In a hydraulic system of the class described, the

combination of an upright cylinder open at its upper end and providedwith a head at its lower portion and an entrance and exit for liquid toand from a chamber at the lower portion of the cylinder above said head;a drumlike piston reciprocable in said cylinder by said liquid, saidpiston comprising a cylindrical body portion and upper and lower heads;bleeding means, including a flexible pipe disposed in the space definedby said heads and the body portion of said piston and opening throughsaid heads, carried by said piston providing a way for escape of air insaid chamber, entrained with said liquid, said way having an opening tosaid chamber through said lower piston head and an opening to theatmosphere through said upper piston head; and releasable means normallyclosing said last mentioned opening.

2. In a hydraulic system of the class described, the combination of anupright cylinder open at its upper end and provided with a head at itslower portion and an entrance and exit for liquid to and from a chamberat the lower portion of the cylinder above said head; a drum-like pistonreciprocable in said cylinder by said liquid, said piston comprising acylindrical body portion, an upper head detachably connected to saidcylindrical body portion, and a lower head; bleeding means, including aflexible pipe connected to said heads and disposed in the space definedby said heads and the body portion of said piston, carried by saidpiston providing a way for escape of air in said chamber, entrained withsaid liquid, said way having an opening to said chamber 7 through saidlower piston head and an opening to the atmosphere through said upperpiston head; and releasable means normally closing said last mentionedopening.

3. In a hydraulic system of the class described, the combination of anupright cylinder open at its upper end and provided with a head at itslower portion and an entrance and exit for liquid to and from a chamberat its lower portion and an entrance and exit for liquid to and from achamber at the lower portion of the cylinder above said head; adrum-like piston reciprocable in said cylinder by said liquid, saidpiston comprising a cylindrical body portion and upper and lower headsand said piston being provided with a screw threaded hole in the lowerhead and with a flexible packing at the under portion of the lower headdetachably connected thereto by retaining means including a bolt, theshank of which is in threaded engagement .with the screw threads of saidhole; bleeding means, including a pipe disposed in the space defined bysaid heads and body portion of said piston, said pipe open to the saidway of the said bolt and to the atmosphere through an opening in saidupper piston head, said bleeder means being carried by said pistonproviding a way for escape of air in said chamber, entrained with saidliquid, said way having an opening to said chamber through said lowerpiston head. and an opening to the atmosphere through said upper pistonhead; and releasable means normally closing said last mentioned opening.

4. In a hydraulic system of the class described, the combination of anupright cylinder open at its upper end and provided with a head at itslower portion and an entrance and exit for liquid to and from a chamberat the lower portion of the cylinder above said head; a drumlike pistonreciprocable in said cylinder by said liquid, said piston comprising acylindrical body portion and upper and lower heads and said piston beingprovided with a screw-threaded hole in the lower head and with aflexible packing at the under portion of the lower head detachablyconnected thereto by retaining means including a bolt, the shank ofwhich is in threaded engagement with the screw threads of said hole;bleeding means, including a pipe disposed in the space defined by saidheads and body portion of said piston, said pipe open to the said way ofsaid bolt and to the atmosphere through an opening in said upper pistonhead, said bleeder means being carried by said piston providing a wayfor escape of air in said chamber, entrained with said liquid, said wayhaving an opening to said chamber through said lower piston head and anopening to the atmosphere through said upper piston head; and releasablemeans normally closing said last mentioned opening, said bolt beingcentrally located wtih respect to said lower piston head and the openingin said upper piston head being eccentrically located, whereby the loadupon said piston may engage upon the center of said upper piston head.

5. In a hydraulic system of the class described, the combination of anupright cylinder comprising a cylindn'cal body member open at its upperend and a head closing the lower portion of said body member, saidcylinder provided with an entrance and exit for liquid to and from achamber at the lower portion of the cylinder formed by said cylindricalbody member and head, and said cylindrical body member provided with acircumferentially extending groove open to its interior adjacent theupper end thereof and an exit way for liquid leading from 'said groovethrough the wall of said cylindrical body member; and a piston slidablyextending into said cylinder, and extending beyond the upper portionthereof, actuated by fluid introduced into said chamber, saidcircumferential groove adapted to receive liquid finding its wayupwardly between said piston and cylindrical body member of the cylinderand exiting from the groove through said piston being provided with alaterally expansible packing at its bottom engaging with intimatecontact the bore of said cylindrical body member, and the lower well ofsaid groove being beveled downwardly and inwardly to facilitateinsertion of said piston carried packing into the cylinder, past saidgroove.

References Cited in the file of this patent UNITED STATES PATENTSGermany Oct. 15,

